package com.dcy.znoa.common.util.password;

/* Copyright 2004, 2005, 2006 Acegi Technology Pty Limited
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
*     http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/

/**
* <p>Convenience base for all password encoders.</p>
*
* @author Ben Alex
* @version $Id: BasePasswordEncoder.java 2217 2007-10-27 00:45:30Z luke_t $
*/
public abstract class BasePasswordEncoder implements PasswordEncoder {
   //~ Methods ========================================================================================================

   /**
    * Used by subclasses to extract the password and salt from a merged <code>String</code> created using
    * {@link #mergePasswordAndSalt(String, Object,boolean)}.<p>The first element in the returned array is the
    * password. The second element is the salt. The salt array element will always be present, even if no salt was
    * found in the <code>mergedPasswordSalt</code> argument.</p>
    *
    * @param mergedPasswordSalt as generated by <code>mergePasswordAndSalt</code>
    *
    * @return an array, in which the first element is the password and the second the salt
    *
    * @throws IllegalArgumentException if mergedPasswordSalt is null or empty.
    */
   protected String[] demergePasswordAndSalt(String mergedPasswordSalt) {
       if ((mergedPasswordSalt == null) || "".equals(mergedPasswordSalt)) {
           throw new IllegalArgumentException("Cannot pass a null or empty String");
       }

       String password = mergedPasswordSalt;
       String salt = "";

       int saltBegins = mergedPasswordSalt.lastIndexOf("{");

       if ((saltBegins != -1) && ((saltBegins + 1) < mergedPasswordSalt.length())) {
           salt = mergedPasswordSalt.substring(saltBegins + 1, mergedPasswordSalt.length() - 1);
           password = mergedPasswordSalt.substring(0, saltBegins);
       }

       return new String[] {password, salt};
   }

   /**
    * Used by subclasses to generate a merged password and salt <code>String</code>.<P>The generated password
    * will be in the form of <code>password{salt}</code>.</p>
    *  <p>A <code>null</code> can be passed to either method, and will be handled correctly. If the
    * <code>salt</code> is <code>null</code> or empty, the resulting generated password will simply be the passed
    * <code>password</code>. The <code>toString</code> method of the <code>salt</code> will be used to represent the
    * salt.</p>
    *
    * @param password the password to be used (can be <code>null</code>)
    * @param salt the salt to be used (can be <code>null</code>)
    * @param strict ensures salt doesn't contain the delimiters
    *
    * @return a merged password and salt <code>String</code>
    *
    * @throws IllegalArgumentException if the salt contains '{' or '}' characters.
    */
   protected String mergePasswordAndSalt(String password, Object salt, boolean strict) {
       if (password == null) {
           password = "";
       }

       if (strict && (salt != null)) {
           if ((salt.toString().lastIndexOf("{") != -1) || (salt.toString().lastIndexOf("}") != -1)) {
               throw new IllegalArgumentException("Cannot use { or } in salt.toString()");
           }
       }

       if ((salt == null) || "".equals(salt)) {
           return password;
       } else {
           return password + "{" + salt.toString() + "}";
       }
   }
}
